1. Field of the Invention
The present invention relates to a method of breeding poultry for food, it relates more particularly to a method of breeding such poultry for food as broilers and the like, characterized in that a specific iodine-containing protein is fed to the poultry in a certain period of time for breeding, thereby to lessen the body-fat and develop muscles in their body.
2. Description of the Prior Art
Referring to poultry for food, particularly broilers, generally when they have been fed for about 60 days after hatching (namely when they have reached the age of 60 days), they are to be shipped to the market. And since poultry that have meager fat and much meat are appreciated as good qualities in the market, various measures have been taken up to this time for the purpose of breeding up such poultry for food as may satisfy the above conditions.
As a method of breeding up poultry to be fleshy, that is, to have increased body-weight, addition of antibiotics or synthetic antifungus agents to the feedstuff is generally practiced, and further addition of hormone drugs is also attempted. However, antibiotics and hormone drugs are not only costly, but also they will produce a considerable effect also upon human bodies, for that reason, the use of antibiotics and hormone drugs are placed under strict regulations by the authorities, and particularly addition of hormone drugs to the feedstuff is not always so easily permitted.
On the other hand, as iodine-type additives to the feedstuff, potassium iodide, potassium iodate and calcium iodate are permitted to be employed; indeed such inorganic iodine may be effective in the treatment of the iodine-deficiency disease, but they have no effect in accelerating growth of the poultry.
It is disclosed in Japanese Patent Publication No. 48-1483, and No. 49-46752 that iodocasein has an effect of thyroxine, and that the hydrolysate of iodocasein has an effect of increasing body weight of animals, but those additives have not been put to the practical use. It is because that the general term "iodocasein" includes various kinds of iodocasein, and they have respectively different contents of iodine, and that a certain kind of iodocasein will induce decrease, instead of increase, in the body weight of the poultry, and that it has sometimes no effect at all on the poultry depending upon the age of the poultry to be fed with the feedstuff containing such additives.